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Relationship between crystallization regimes and melting phenomena in isotactic polypropylene

✍ Scribed by A. Celli; A. Fichera; C. Marega; A. Marigo; G. Paganetto; R. Zannetti

Publisher: Elsevier Science
Year: 1993
Tongue: English
Weight: 249 KB
Volume: 29
Category: Article
ISSN: 0014-3057
DOI: 10.1016/0014-3057(93)90305-y

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✦ Synopsis

A study has been made of the relationship between crystallization regimes and multiple peaks in the melting endotherms ofisotactic polypropylene 0PP). Some samples of this polymer can show multiple melting peaks in differential scanning calorimetry (DSC) scans: this phenomenon has been studied and associated with a regime Ill of crystallization, giving rise to a phase which appears disordered from a crystallographic point of view. During melting, this phase recrystallizes, giving a more ordered phase which melts at a higher temperature. On the contrary, crystallization in regime H produces a crystalline phase which melts with a single endotherm. These phenomena have been studied by DSC, by optical microscopy in polarized light and by X-ray diffraction; the results are discussed in terms of the proposed interpretation.

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